This invention relates to the deployment of inflatable structures, and more particularly to a pressurized actuator system that utilizes pneumatic or hydraulic force for initiating the reliable rapid deployment of inflatable structures.
Certain types of aircraft, such as commercial fixed wing aircraft and rotorcraft such as for example, helicopters, are required by the regulatory agencies to carry inflatable flotation devices for passenger safety in the event of an emergency situation over water. Fixed wing commercial aircraft, for example, typically include one or more inflatable slides that are normally stored uninflated in a container mounted on the interior of the aircraft door or immediately adjacent thereto.
In military applications, inflatable life rafts and their inflation systems are sometimes located in external compartments of the aircraft in order to maximize space in the fuselage for transporting equipment, supplies and personnel. Multiple life rafts and their inflation systems may be located in the external compartments. In the prior art the inflation system for each life raft includes a container of pressurized gas with an inflation valve that can be actuated from a remote location, such as the cockpit, by mechanical means which may be in the form of a cable and pulley system routed through the aircraft. When a pull handle or similar device associated with the system is activated, the valve is opened and the pressurized gas is discharged from the container and into the life raft causing its rapid inflation. Some of such inflation systems employ a secondary applied force for discharging a secondary pressurized fluid to indirectly activate the primary inflating system. An example of such systems has been disclosed in U.S. Pat. No. 6,644,596. It should be noted however that such prior art deployment systems are typically adapted for deployment of a single inflatable structure and not necessarily concentrated on controlled and/or independent deployment of emergency evacuation floats and associated life rafts.
Mechanical inflation systems for rotorcrafts have also been employed in order to enable the rotorcraft to land on water in an emergency situation, such as when the rotorcraft loses power. Such systems provide passengers with extra crucial time to escape before the rotorcraft sinks. The inflation system typically includes multiple emergency flotation devices mounted to the rotorcraft landing gear, a container of pressurized gas for each flotation device, an inflation valve associated with the pressurized container, and a mechanical system routed through the helicopter for actuating the inflation valves. Thus, great care must be taken to ensure that the cables are properly sized, sufficiently taut, lubricated, and in good working order so that the flotation devices may be simultaneously deployed.
Although other systems or mechanisms can be used for deploying the flotation devices and life rafts, they have their own disadvantages. By way of example, an electrical system might employ a solenoid valve that is actuated upon supplying a voltage. Likewise, a pyrotechnic mechanism uses an explosive charge inside the valve for its activation. However, when an emergency landing situation occurs due to a loss of rotorcraft power, the emergency flotation devices may not be deployed since there may not be enough electrical current to actuate the solenoid valve or set off the explosive charge.
For the rotorcrafts such as helicopters that fly missions over water it is required to carry emergency primary inflatable devices such as floats and secondary inflatable devices, life rafts for example, to allow passengers to egress after a water ditching or landing. Typically, the inflatable floats are mounted to the skids or fuselage of the rotorcraft and are designed to keep the aircraft afloat on the water. The inflatable rafts can be stowed inside the cabin or mounted to the fuselage exterior. Prior to the water landing, the pilot activates the inflatable floats by pulling a handle, lever or similar activation means. Before exiting the rotorcraft, the crew must locate and remove the inflatable rafts. After exiting the aircraft, the inflatable rafts are inflated using another activation device.
When mounted externally, it is advantageous to remotely activate such inflatables. Along with remote mounting comes a possibility of inadvertent deployment of the life rafts either during flight or during ground maintenance. If the raft inflates in flight, it may become entangled in the main or tail rotors and cause the pilot to lose control of the rotorcraft ending in loss of life. On the other hand, inadvertently, activation of the inflatable could cause serious injury to unsuspecting maintenance personnel.
Thus, there is a long felt need for a deployment system having an inherent safety feature, so that the secondary inflatable or the life raft can be activated only after the primary inflatable or float has been deployed. There is further need for the deployment system eliminating the chance of the life raft being inadvertently deployed either in-flight or during ground maintenance operations. It would be further desirous to provide an actuator system that ensures the independent and controlled deployment of the flotation devices and life rafts.